New ways of administering testosterone could herald the end of frailty

ELEANOR HALL: Now to those Australian researchers who say they've have made a discovery that could mean the end of frailty in old age.

It's long been known that testosterone promotes muscle growth.

Now the researchers at Sydney's Garvan Institute say their research into delivering small doses of testosterone directly to the liver may stop muscles wasting away in old age.

Simon Lauder has our report.

SIMON LAUDER: The weakening of the body is seen as an inevitable part of ageing. Researchers at the Garvan Institute of Medical Research have made a discovery which they say could help stop that.

Endocrinologist, professor Ken Ho, says it could have major public health implications.

KEN HO: Given the scale of frailty in elderly population and the scale of dysfunction that arises as a result of protein wasting from a whole range of medical diseases which in our view is preventable.

SIMON LAUDER: So do you think that this shows that we're able to avoid one of the big drawbacks of ageing and that is the frailty?

KEN HO: Correct. So ageing is a very, very complex process but one of the consequences of ageing is frailty and frailty arises from a loss of muscle mass. And it is my view that if our invention or discovery achieves what we predict it to do, then it would be a substantial contribution to this aspect of public health.

SIMON LAUDER: The benefits of testosterone therapy can be outweighed by the side effects. Too much can poison the liver. Testosterone on the brain can cause aggression. It can damage the muscles of the heart and it can cause unwanted hair growth.

KEN HO: Our invention is really quite simple. We have made the discovery that the ability of testosterone to build protein in the body works through the liver. And we tested this by exposing the liver solely to testosterone by taking a small dose of testosterone by mouth. This means that after absorption, the liver is the first organ exposed to testosterone.

The liver then metabolises the testosterone so that none of this hormone spills into the peripheral circulation. And as a result of that, all body tissues and organs apart from the liver do not get exposed to the hormone.

SIMON LAUDER: Professor Ho says this method stimulated protein synthesis at about the same level achieved by other, more risky methods.

He says a small study on post-menopausal women has proved the concept. Now a larger study is needed to investigate the long term effect of oral testosterone on muscle mass and function.

Professor Ho says the benefits could be enormous for a wide range of people.

KEN HO: Patients with chronic kidney disease and in many, many chronic conditions that can cause muscle wasting. So the potential is enormous.

SIMON LAUDER: The findings have been published in the European Journal of Endocrinology.